I have made all sorts of sound players, LED controllers based on the Arduino platform.
SoundHide featured a twin stereo sound player amplifier setup and also included two sample players activated by buttons on the soundboard outside the installation.
For Roger Eno I made the Phone simulator for the Phone Box at Snape Maltings as part of SNAP in the Aldeburgh Festival. It rang every 7 minutes and if people picked it up they heard a voice telling them to wait and then various clips including Benjamin Britten talking.
For Brian Eno I have developed an LED system to allow him to make lightboxes that change colour very slowly. Each box has at least 3 channels and these can be programmed individually to make wonderful art.